Electropneumatic brake



May 28, 1935. E, E. HEWITT 2 2,002,892

ELECTROPNEUMATI C BRAKE v 7 Filed July 12, 1934 2 Sheets-Sheet 1 INVENTOR I ELLIS E. HEWITT :BY I

ATTOR Y v Q \1 KO w.

May 28,1935. E. EJHEWITT ELECTROPNE EUMATIC BRAKE Filed July 12, 1934 2 Sheets-Sheet 2 M MQ mm mw 93 wk \m\ aZZZ L m Q E Wm m w Q INVENTOR.

ELLIS E. HEWITT.

A TTORNE Y.

Patented May 28, 1935 I ELECTROPNEUMATIC BRAKE Ellis E. Hewitt, EdgewoodQPa assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application July 12, 1934,. Serial No. 734,770

'6 Claims. (01. 303-45) This invention relates to electro-pneumatic brakes and has particular relation tocontrol means therefor. I A

In the co-pendingapplication of Donald L.

I McNeal, Serial No. 718,961, filed April 4, 1934, and

assigned to the assignee of this application, there is disclosed control means, for the brakes on a train, operable to simultaneously initiate the operation of electrical brake controlling devices on the cars an'd the operation of'pneumatic brake controlling devices on the locomotive and cars not having electrical brake controlling devices;

The control means disclosed in the said copending application comprises essentially a combin'ation brake switch and valve device so mechanically interlocked with the usual automatic brake valve on the locomotive, that movement of the former to a service application position causes the latter to be movedto a lap position to out ofi the supply of fiuid'under pressure to the brake pipe, the valve portion of the combination switch and valve device operating to cause fluid at reducing valve pressure to be supplied to the locomotive distributing valve device whereby the locomotive brakes are applied without further movement'of the automaticbrake valve or any movement of the usual independent brake valve being required.

The principal object of my invention is to provide means for permitting the brakes on the locomotive and cars to be operatively controlled bya combined brake switch and valve device, as in the above mentioned co-pending application but without requiring any movement of either the automatic brake valve or of the independent brake valve. v I r More specifically, it is an object of my inventionrto pneumatically interlock a combination brake switch and valve device with the usual automatic brake valve and independent brake valve in such manner that no movement of the automatic brake valve or independent brake valve is required upon operation of the combination brake switch and valve device. 7

A further object of my invention is to provide a combination brake switch and valve device adapted to function in a novel manner as hereinafter described.

Other objects and advantages of my invention will be made apparent in the subsequent description of my invention when read in connection with the accompanying drawings, wherein Figure 1 is a diagrammatic view, principally in section,

illustrating the essential features of one embodi ment of my invention,

Figure 2 is a diagrammatic view, showing-the various pneumatic and electrical connections efiected by the combination brake switch and valve device which I have devised and which-is employed in the embodiment shown'in Figure 1,

Figure 3 is a diagrammatic view, showing the various pneumatic connections'efiected' by the automatic brake valve employed in the embodiment shown in Figure 1, and

Figure 4 is a diagrammatic view, partly in section, illustrating a modified form of my invention. I I

It should be understood'that the drawings dis close only the essential features of my invention as embodied in the controlequipment on a con-'- trol car, suchas the locomotive, and that :such equipment is adapted to function in cooperation with brake controlling equipment onfthe cars, which equipment is not shown but which may be of any suitable character, either in respect to electro-pneumatic or pneumatic operation, such as, for example, that shown and describedin the above-mentionedoo-pending application or the co-pending application, Serial No, 507,783""o ffi Clyde C. Farmer,-filed January 10, 1931 and as- V signed to the assignee of thisapplication.

The embodiment of my invention shown in Figure l,comprises a brake pipe ll, train wires l2,"|3 and l4, designatedhereinafter as-thefa'p' plication wire, the returnwire,-and the release wire, respectively, and control car or locomotive equipment including a brake controlling; valve device, such as the distributing valve deviceIS, a standard automatic brake valve device IS, a standard independent brake valve device 11, a

combination brake switch and valve*device" l8,

a mainreservoir l9, an equalizing reservoir 20, a brake cylinder 2| for'the locomotive, a reduc ing valvedevice 22, a feed valve" device 23, and an electric current generator 24, illustratedas of a direct current type, but which may be'of'an alternating .current'type if the electrical control equipment on the cars is adapted to operate on alternating current I c 7 The combination electric brake :switch and valve device l8 comprises a sectional casin'g having a switch portion 3|, a valve portion 32 and a cut-ofivalve portion 33. r

- The switch portion 3| is 'similar'to the usua brake switch construction and may comprise a chamber 34 containing stationary'contact members 35, 36, and 31 securedin insulated relation to the walls of the chamber and a rotatable drum latching the handle 43 in various brake operating positions.

Contact member 35 is connectedto one brush terminal 44 of generator '24 bya wire or conductor 45, the opposite brush terminal 46 of the I generator being connected to-the return wire !3 by a conductor 41. are connected to the release wire l4 and tothe application wire I2, respectively, by conductors and? 49.

As shown in Figure 1 and also in Figure 2, in

therelease position of the brake switch, no con- .nection is established between contact member 95 and either of. the contact members 36 and 31,

and thus the application magnet circuit in-:

cluding train wire 12, and the release magnet circuit including train wire l4; are both deenergized. V 1

When the brake switch handle-43 is in service application position,-,contact members 31 andfifi are connected tocontact member '35 by bridging members and39', respectively; so: that both the application magnet circuit and the releasemagnet circuit are, energized. 'When; the brake switch handle 43 is in lap position; contactmember 39 only is connected togcontactmember 35, through bridging; member. 39, so that only the releasemagnet circuit is energized. 7 I

Thevalve portion 32 of the combination switch and valve device l8comprises a chamber 52, separatedqfrom chamber 34 of the switch portion 3| by, aiwall? 53, and'a rotary valve 54v contained in the chamber 52 and operating on-a valve seat 55. The, operating stem 4| extends through an openi-ng 8;in"the'wall 53 into chamber '52, and the end portion. of-the. stem is suitably interlocked with; the rotary valve, 54 so that rotary movement of handle 43 effects corresponding rotary movement of the valve. A spring 59,,int'erposed between the end of the stem-4i and the valve 54 and contained inwa recess 5'! 'in the stem, serves to bias thev stem upwardly to press a.

flanged portion oil-the stem; into engagement with a sealinggasket 59 supported on the wall 53 and surrounding the opening 58in the wall. 'Ihus, ,in.,the;op.eration of the handle 43 into the'var-ious brake operating positions, pneumatic communications are established as; hereinafter described, simultaneously with the establishing of electrical connections through the switch portion. 3].

Thecut-ofi valve portion 3a of the switch and valve device l8 comprises a chamber 62 continuously connected to rotary valve chamber 52 otthebrakevalve portion 32 through a passage Gland having a; valve piston 64, of cup shape,

closely fitted therein which is provided with. a sealing disc or gasket 65in the face thereof for engaging an. annular; seat rib 99 and thereby cutting off the communication between chembers.52, 62 and a passage li'l leading to the automatic, brake valve, l6 when the piston is in'its lowermost; position.v Piston ($4 is raised by fluid A suitable latchin Contact members 36 and 31 under pressure in chamber 62 acting on the face thereof against the opposing force of a spring 68 disposed between the back side of the piston and the end wall of the casing portion 33, in a chamber69.

The annular rear edge 19 of piston 64 is suitably rounded and is adapted to engage a sealing gasket 1] secured in the casing and thereby cut off communication past piston 64 between chamber 69 and chamber 62, when the piston is in its :uppermost position.

The distributing valve device I5 is of standard construction and comprises the usual equalizing through a passage 19 to a pressure chamber 89.

The application valve portion includes a piston 82 contained in piston chamber 83, an application slide valve 84 contained in a chamber 95,

and an exhaust or release slide valve 85 containedin a chamber 81, both slide valves being adapted tobeoperated by the piston 82.

The automatic brake controlling valve device I6 is of standard construction and comprises a sectional casing 99 having a chamber 92 containinga rotary valve 93 adapted to be operated in the usual manner. by a handle 94. The auto matic brake valve device 16 also comprises an equalizing piston HUI having an equalizing chamber 99 at one side thereof connected to the equalizing reservoir 29 through a connecting pipe and passage I93, At the opposite side of the equalizing piston I0! is a chamber I92 which is inconstant communication with the brake pipe Il The equalizing piston IOI is adapted to operate a vent valve 94 in the usual manner to cause fluid under pressure from the brake'pipe to be exhaustedthrough a vent passage I95 at a service rate.

The independent brake valve device I! is of standard construction and comprises a sectional casing having a chamber I99 containing a rotary .regulate the pressure of fluid supplied therethrou'gh to '70 pounds With the automatic brake valve device l6 and the independent brake valve device I! in running position and the combination brake switch and valve device l8 in release position, as shown in Figure l, brake pipe ll is charged with fluid under pressure at feed valve pressure from the main reservoir l9 through pipe H2, feed valve device 23, pipe and passage H4, rotary valve chamber 52, passage 63, chamber 62 of the cutoff valve device, passage 91, passage and pipe H5, cavity H6 in rotary valve 9 3' of the automatic brake valve device l6, and passage and pipe H fluid under pressure being concurrently supplied to the equalizing reservoir 29 and equal- .izing chamber 99 from cavity, I [6 in rotary valve 99 through apassage Ill, and to chamber I02 brake pipe.

passage Fluid under pressure from the brake pipe is also supplied through pipe andpassage I3 to piston chamber 12 of the equalizing valve portion of the distributing valve device I 5, piston 14 being moved thereby to uncover :the usual feed groove around the piston, whereupon fluid under pressure flows through the feed groove into slide charged to brake pipe pressure. 7

valve chamber I8 and thereafter through passage 19 to the pressure chamber 80, which is thus T Rotary valve chamber 92 of. the. automatic brake valve device I6 is charged with fluid under pressure at main reservoir pressure from the main reservoir I9 through pipe II.2, and'branch pipe andpassage .I I9, fluid under pressure from pipe I I2 also being supplied through branch pipe and passage I20. to the application valve chamber of the distributing valve device-I5;

Fluid under pressure .as regulated by the reducing valve device 22 is supplied to rotary valve chamber I09 of the independent brake valve device I! from the main reservoir I9, through pipe II 2, branch pipe I22, reducing valve device 22 and pipe and passage I23,fluid under pressure from the'pipe I23 being supplied also through a branch pipe I24 to the seat of the rotary valve, 54 ofthe combination brake switch and valve device l8.

If it be; desired to effect a service application of the brakes by electrical control, the combination brake switch and valve device I8 is moved to service position wherein bridging members 39 and 40 connect contact member 35 .to

contact members 36 and 31, respectively, and rotary valve 54 serves to connect chamber 52 above the rotaryvalve with chamber 69 back of; the cut-01f valve piston 64 through a passage I28 and a cavity or port I29 in the rotary valve (Figure 2), as well as to connect the branchpipe I24 of the reducing valve pipe I23 with a pipe I3I leading to the distributing valve device I5,

through a cavity I32 (Figure 2) in the rotary valve. v e

- When the pressure of the fluid supplied to the backof cut-off valve piston substantially balances the pressure of the fluid in chamber 62 of the cut-off valve device, spring 68 causes piston 64 to be moved downwardly into seating engage ment on the annular rib seat 66, thereby cutting off the supply of fluid under pressure through feed valve device 23 to the brake pipe lI,and isolating the brake pipe system.

The energization of the application and re-' lease magnet circuits, including application wire I2 and release wire I4, respectively, effected by the operation of the combined brake switch and valve device IE to service position, efiects the serviceapplication of the brakes on all the cars equipped with electro-pneumatic brake controlling, devices in the-usual manner.

As' the fluid under pressure in the auxiliary reservoirs on the cars equipped with electropneumatic brake controlling devices is supplied to'the brake cylinders on those cars, the fluid under pressure in brake pipe II flows through the usual feed grooves around the pistons in the pneumatic brake control devices on those cars due to the reduction in the fluid pressure in the usual manner upon charging of the corresponding auxiliary reservoirs: and'ithus a reduction in the pressure of the fluid throughout fluid supply effected by cut-off valve'piston. 64.

Such reduction in brake pipepressure actsin the same manner as the usual reduction in brake pipe pressure effected at a service rate by operation of the automatic brake valve device I6, to cause operation of the pneumatic brake controlling devices or triple valves on the cars not equipped with electro-pneumatic brake controlling devices, which operation results''in a service application of the brakeson those cars. I

With the combination brake switch and valve device I8 in service position, fluid is supplied to the application valve .piston chamber 83 of the distributing valve device I5 on" the locomotive through reducing valve device 22, pipes. I 23 and [24, cavity I32 (Figure 2) in the rotary..valve54,

pipe and passage I3I, a cavity in the main slide valve '16 of theequalizing valve portion of 4 the distributing valve device, passage I 36, and. branch passage I31.

An application chamber I38 in the distributing valve device is also charged with fluid under pressure through a passage I 39 connected to passage I3I by cavityl35 in the main slide valve of theequalizing valve portion. 7

therein registers with a passage I45 connectingvalve chamber 85to valve chamber 81;. Thus, the brake cylinder exhaust passage is cut off and fluid under pressure from the main reservoir I9 is supplied to the brake cylinder through pipe H2, branch pipe I20, valve chamber-85, port I44, passageMS, valve chamber 81, passage-I46 and passage-and pipe 1, to efiect an application of l the brakes on'the locomotive.

Due to the time lag incident to the reduction in brake pipe pressure effected-as previously described, there is some time interval between the operation of the combination brake switch and valve device I8 to service position and the 'reduction in the fluid pressure in equalizing piston chamber I2. However, when the pressure, of the fluid in piston chamber I2 reduces in accordance 'with the reduction in-brake pipe,pressure,1equalizingpiston I4 is moved tothe right by the excess of fluid pressurein chamber 80, in the usual manner, thus first causing'auxiliary slide valve H to: move to uncover a passage I493in the main slidevalve I6 at the seat of the auxiliary slide valve and then causing themain slide valve I6 to be moved intosuch position that passage I49 registers with passage I36,the application chamber I38 being connected to passage I36 through passage I39 and a cavity I5I in'the main slide valve. In this position of the main slide valve I6,

the communication from reducing valve device 22 to the application piston chamber i'scut ofi by V the lapping of passage I3I at the seat of the main slide valve; Thus depending on the rapidity with which'the brake pipe pressure reduction is effected, more or less fluid is supplied to the a plication piston chamber 83 and application chamber I38 through the reducing valve device.

Whenthe equalizing piston I4 is operated,v-;as

brake switch tact" member 36 is connected to contact member.

just. des'cribedffluid under pressure from pressurei'chamber 80, being at a higher pressure than the attained pressure of fluid supplied to theapplication piston chamber '83 and the application chamber I38 through the reducing valve device 22, flows into piston chamber 83 and chamber I38 throughpassagev I9; slide valve chamber I8, passage I49 in the main slide valve I6, and passage I36, thereafter dividing and flow ing'to'piston chamber 83 through passage I31 and to chamber I38 through cavity I5I in the main slidevalve I6 andpassage I39. .When the pressureof the fluid in slide valve chamber 18 decreases-below the reduced brake pipe pressure effective in piston chamber-I2, the piston I4: is moved tothe left, as viewed in Figurefl, a suflicient distance to cause auxiliary slide valve TI. to lap the passage I49 in the main slide valve and thus cut off the further supply of fluid under 'pressureto the application piston chamber 83 and application chamber I38. When the pressure of the fluid built up in brake cylinder 2| by fluid supplied thereto from the main reservoir I9, and acting on the back of piston 82 through passage'MI while application "piston82 is in application position, exceeds that in application piston chamber 83, piston 82 is moved to theleft, as viewed in Figure 1, to cause the application slide valve 84 to lap the passage I45 and-thus cut oii the further supply of fluid underpressure to the brake cylinder. When the supply of fluid under pressure to the brake cyl inder is cut off; as just described, further. movement of'piston'82 to the left ceases and thus release =slidefvalve continues'to lap the exhaust passages I'4I and I42 and thereby'maintain. the rakes applied on the locomotive.

' In' the above: operation, it is assumed that a suflicient number of cars are equipped with electro-pneumatic brake controlling devices so that an adequate and sufficiently rapid reduction in brake pipe pressure'will be efiected when the combination brake switch and valve device I8 isoperated to service position, to cause a service application of the brakes on the cars equipped solely with pneumatic brake controlling devices.

The handle 43015 the combination brake switch andvalve device I8 is held inservice position only long enoughto obtain the desired degree of service application, it being then moved to-lap positionwherein only contact member36 of'the brake switch portion is connected to contact member 35 and wherein the rotary valve 54 is positioned to maintain communication through a cavity I48'therein (Figure 2) between chamber 52, which is in communication with the feed valve'pi'pe II4, and'chamber 69 at theback of cut-off valve piston 64, whereby the piston remains in seating relation onthe annular rib seat.

'66 to maintain the isolation of the brake pipe system from the source of fluid supply. I Since, in the lap position of the combination and valve device I8, only the con- 35, only the release magnet circuit including release wire I4 is energized, the application magnet circuit including application wire having been opened. As a result, only the release magnets of the 'electro-pneumatic brake controlling devices on the cars remain energized. Further supplyof' fluid under pressure from the auxiliary reservoirs on the cars equipped with electrobrake controlling equipment to the as a-result. reduction-in brake pipe pressure by flow-of fluid through the feed grooves, past'the triple valve pistonsonthosecars, ceases when the brake pipe pressure falls below-auxiliary reservoirqpressure andeffects movement-of'the triple valve pistons to close the feed grooves.

.' The pneumatic brake controlling devices on the cars,- solely so equipped, thus move to lap position" in the usual ,manner, when auxiliary reservoir .pressureialls below the pressure. to

which the fluid in the brake pipe has fallen.

The brakes on :all the cars are thus held applied in the attained degree of pressure in'the brake cylinders.

. Successive movements. of the handle 43 of the combination brake switch and valve device I8 to service'positio'n followed by movement tolap position, effects with each step, an increasing degree of braking power until full service application is attained.

'If it be desired to'release the'brakes electrically, after an electrically effected application as above described, the combination'brake switch and valvedevice I8 is moved to release position, wherein both'the application "and release magnet circuits are deenergized, and therotary valve 54 establishes communications as shown in Figure 1, including that from passage I28 opening'into chamber 69' at the back of cut-off valve piston 64 toan exhaust port I53 through a cavity I54 in the 'rotary'valve 54, and that from distributing valve release pipe I 3I' toa pipe I55 leading to the independent brake valve device I! through a cavity I56 in the rotary valve 54.-

Simultaneous deenergization of both the application and release magnet circuits effects deenergization of the application and release magnets of the electro-pneumatic' brake controlling devices on the cars to effect a release of the brakes in the usual manner. I I

The connectionof chamber 69 back of cut-off valve piston 64 to exhaust port I53 causes venting of the fluid under pressure'therein' and when a sufficient reduction has been made,' the fluid pressure acting on the face of piston 64 forces the piston upwardly against the opposing biasing force exerted by spring 68 until the rounded annular rear edge ID of the piston 64 engages the gasket II and seals chamber 62 against fluid leakage 'past the 3 piston 64'into exhaust passage I28. U I v The, communication. previously described, is thus established between the -'feed valve pipe I I4 and the brake pipe II and the charging of the brake pipe effectsmovement of the pneumatic brake controlling valve devices on the cars solely so equipped to release position in the usual manner whereby the release of the brakes on those cars is efiected. Fluid under pressure from the brake pipe charges the auxiliary reservoirs on all the cars'in the usual manner.

The fluid under pressure supplied to the equalizing piston chamber I2 from brake pipe I I forces the piston I4 into-release position, shown-in Figure 1. so that pressure chamber 80' is again charged to brake pipe pressure as-previously described. Whenthe equalizing main slide valve I6 is in release positionga communication is established for venting application piston'chamber 83 to atmosphere and thereby efiecting release of the locomotive'brakes, whichcommunication extends from chamber 83 through passages I31 and I36, cavity;l35 in the equalizing slide valve I6,

passage andpipe I3I, cavity I56 in rotary valve tary valve I08, port'and passageylfil, pipe and passage I62 to the seat of the rotary valve 93 of.

the automatic brake valve device I8, and thence through a cavity. I63 inthe rotary valve 93, and

an exhaust passage and portv Win the automatic brake valve. 7

When thebrake cylinder pressure acting on the back of application piston 82; sufiiciently overcomesthe' diminishing fluid pressurein piston chamber. B3.it forces the piston482intd release.

position shown in Figure 1, wherein the. release slide valve .86 uncovers exhaust port and passage I42 and port I43 also registers with branch passage. I41 thereof, so that chamber8'l and the locomotive brakecylinder 2| are connectedto atmosphere and the fluid under pressure inthebrake. cylinder is vented to effect release of thelocomotive, brakes.

Since the electrorpneumatic brake control. ling equipment onthe cars is, adapted also for pneumatic, operation, the automatic brake valve device I6 maybe. operated in the usual manner toeffect the operation of the brakes on the cars and the locomotivepneumatically.

The independent brake valve device I] may also beoperated to effect: the operation of the locomotive brakes in the usual manner. For expipe and passage I68, a cavity-in the rotary valve I68 (not shown), and an exhaust passage. I69, so that the pressure of the fluid in the piston chamber is decreased. The piston 82 is accordingly operated, as for the release operation previously described, to decrease the brake cylinder pressure. When the desired reduction in braking efiect is produced, independent brake valve device I1 is again returned to running position.

In the modified form of my invention, shown in Figure 4, the connections of the main reservoir l9 and the feed valve device 23 in the system vary from that shown'in Figure 1. In Figure 4, the main reservoir I9 is connected directly to the rotary valve chamber 52 of the combination brake switch and valve device I8 through pipe H2 and a branch pipe and passage I12, and feed valve device 23 is connected in pipe I I5 leading from the chamber 62 of the cut-off valve device to the automatic brake valve, I 6, branch pipe H9 leading to chamber 92 above rotary valve 93 of the automatic brake valve [6 being connected to pipe H5 between the feed valve device 23 and the cut-off valve device.

Essentially, therefore, the modified arrangement shown in Figure 4 diiTers from the arrangement shown in Figure 1, in that the cut-off valve device piston 64 controls the supply of fluid under pressure from both the feed valve device 23 and the main reservoir IE to the automatic-brake valve I6 instead of only the supply of fluid under pressure from the feed valve device to the automatic brake valve as in Figure l. V

The operation of the embodiment shown in Figure 4 to eifectl the operation of the brakes is substantially identical with that already described for that shown in Figure 1, except that fluid under pressure from the main reservoir I9 is p'resent in rotary valve chamber 52 andchambers t2 and ,69 of the cut-off valve device. It is, therefore,

deemed unnecessary to specifically describe the operation of the embodiment shown in Figure 4.

Summarizing,- my invention comprises means including a combination brake switch and valve device, for eliecting electrically the operation of the brakes on all'cars of a train andthe loco-' motive, some of the cars being equipped with electro-pneumatic brake controlling! devices and pneumatic brake controlling devices while the 10. comotive and= other-cars are equipped solely;with

the usual pneumatic brake controlling devices.

; The .combinationbrake switch and valvedevice comprises a brake switch portion for eiiecting the;

control of electro-responsive brake controllingequipment on the cars so equipped, anda valve portion adapted to operate simultaneouslyzwithi the brake switch portionfor cutting off theusual release or exhaust communication for the brake.

controlling valve device on the locomotive without requiring movement of either the usual automatic V brake. valve device or the usual independent brake valve device, and. also to control the. operation of a cut-off. valve device for isolating the. brake pipe from the source of fluid supply, as well as to control a communication forsupplying fluid"un-' der pressure from the usual reducingvalvedevice to theusualzdistributing valve device on the 10- comotive. V

Upon a brake application, effected electrically; by operation of the combination brake switch and: valve device to the service position, thereduction in brake pipe pressure, caused by the flow of fluid under pressure from the brake pipe intothe-auxiliary reservoirs on the cars equipped with electro-p-neumatic brake controlling .devices, these auxiliary reservoirs having discharged fluid under pressure, into their associated brake cylinders in response to the operation of electrical control devices on the cars, effects the operation of the pneumatic brake controlling devices on the cars solely so equipped, in the usual manner as for a brake, pipe'reduction initiated by operation of the usual automatic brake-valve on the locomotive.

' By means of my invention, it ispossibleto ema ploy electro-pneumatic brake controlling devices on some cars of a train, without requiring all the cars of a train to be so equipped. Furthermore the combination brake switch and valve device is so pneumatically interlocked with the usualautomatic brake valve device and independent brake valve device that no movement of the latter two brake valve devices is required upon operation of the combination brake switch and valve device.

, While only two embodiments of myinvention have been illustrated and described, it will be understood that various changes, omissions or additions therein may be made, without departing from the spirit thereof. I desire, therefore, that the scope of my invention be limited only as required by the prior art and as defined in the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a brake system, the combination with a brake pipe, a source of fluid under pressure, and a brake valve device for controlling a communication through which fluid under pressure from said source is supplied to said brake pipe and for varying the pressure of fluid in said brake pipe to effect the operation of the brakes: pneumatitrically the operation of the brakes, and fluid pressure responsive means operatively controlled by movementof said brake switch for cutting 01f brake pipe, a source of fluidi under pressure, anda brake valve device for controlling'a communi cation throughwhich fluid under pressure from the supply of' fluid under pressure from said source to said brake valve device through said communication. a 7' 2. In a brake system, the combination with a brake pipe,v a source of fluid under pressure, and a brake valve device for controlling a communication through which fluid under pressure from said source is supplied to said brake pipe and for varying the pressure of 'fluid in said brake pipeto efiect the operation of the brakes pneumatically, of a brake switch operative to service position to effect electrically a service application of the brakes, and a movable abutment normally alposition topermit the supply of fluid under pressure from said source to said brake pipe through said communication and adapted to bemoved to a position for closing said communication, upon the operation of said brake switch to service position. v

3. In abrake system, the combination with a said 'sourceis supplied to' said brake pipe and for varying the pressure of fluid in said brake pipe to effect the. operation of the brakes pneumatically, of a brake switch operative to service position to effect electrically a service application of the brakes, valve means operable upon operation of said brake switch, and fluid pressure responsive means operativelyv controlled by said valve means for closing said communication when said brake switch is in service position.' 7

4. In a brake system, the combination with a :brake pipe, a source of fluid under-pressure,- a

feed valve device for regulating" the supply of fluid under pressure to said brake pipe from said source, and a brake valve device for controlling the supply of fluid under pressure from said feed valve device to said brake pipe and for varying the pressure of fluid in said brake pipe to effect the-operation of the brakes pneumatically, of a brake switch operative to service position to effeet a service application of the brakes electrically, and fluid pressure responsive means adapted,

, upon the operation of said brake switch to service position to-cut ofi the supply of fluid under pressurefromsaid feed valve device to the said brake pipe.

5. In a brake system; the combination with a brake pipe, a source of fluid under pressure, a feed valve device for regulating the supply of fluid under pressureto said brake pipe from said source, and a brake valve device for controlling the supply of fluid underpressure from said Ieed valve device to said brake'pipe and for varying the pressure of fluid in said brake pipe to effect the operation of the brakes pneumatically, of a brake switch operative to'efiect the operation of the brakes electrically, and fluid pressure responsive means adapted, upon the operation of said brake switch to effect an application of the brakes, to cutoff the supply of fluid under pressure from said source to said'feed valve device.

6. In a brake system, the combination with a brake pipe, a'source of fluid under pressure, and a brake valve device for controlling a communication through which fluid under pressure from said source is supplied to said brake pipe and for varying the pressure of fluid in said brake pipe to effect the operation of the brakes pneumatically, of a brake switch device normally in release position and adapted to be moved-toserviceposition to initiate electrically a service application of thebrakes and to lap position to maintain the brakes 

